use "0 B" instead of 0 for empty files

app/src/main/java/com/simplemobiletools/filemanager/adapters/ItemsAdapter.java

@@ -69,7 +69,7 @@ public class ItemsAdapter extends BaseAdapter {
     private String getFormattedSize(FileDirItem item) {
         final long size = item.getSize();
         if (size <= 0)
-            return "0";
+            return "0 B";
         final String[] units = {"B", "kB", "MB", "GB", "TB"};
         final int digitGroups = (int) (Math.log10(size) / Math.log10(1024));
         return new DecimalFormat("#,##0.#").format(size / Math.pow(1024, digitGroups)) + " " + units[digitGroups];